Overview of articles published by TracVac partners.
1. A Chlamydia trachomatis VD1-MOMP vaccine elicits cross-neutralizing and protective antibodies against C/C-related complex serovars
Anja Weinreich Olsen1, Ida Rosenkrands1, Martin J. Holland2, Peter Andersen1,3 & Frank Follmann1
1 Center for Vaccine Research, Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark
2 Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
3 Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
Ocular and urogenital infections with Chlamydia trachomatis (C.t.) are caused by a range of different serovars. The first C.t. vaccine in clinical development (CTH522/CAF®01) induced neutralizing antibodies directed to the variable domain 4 (VD4) region of major outer membrane protein (MOMP), covering predominantly B and intermediate groups of serovars. The VD1 region of MOMP contains neutralizing B-cell epitopes targeting serovars of the C and C-related complex. Using an immuno-repeat strategy, we extended the VD1 region of SvA and SvJ to include surrounding conserved segments, extVD1A and extVD1J, and repeated this region four times. The extVD1A*4 was most immunogenic with broad cross-surface and neutralizing reactivity against representative members of the C and C-related complex serovars. Importantly, in vitro results for extVD1A*4 translated into in vivo biological effects, demonstrated by in vivo neutralization of SvA and protection/cross-protection against intravaginal challenge with both SvA and the heterologous SvIa strain.
2. A Flow cytometry based assay to determine the phagocytic activity of both clinical and non-clinical antibody samples against Chlamydia trachomatis
Marco Grasse1,2, Ida Rosenkrands1, Anja Olsen1, Frank Follmann1 and Jes Dietrich1
1 Department of Infectious Disease Immunology, Statens Serum Institut, Copenhagen, Denmark.
2 Department of Immunology, Institute for Biomedical Aging Research, Universität Innsbruck, Innsbruck, Austria.
Antibodies play a crucial role in the defense against infection and can be protective due to their ability to mediate phagocytosis and/or neutralization. Vaccine development could greatly benefit from a method to measure functional C. trachomatis-specific antibodies in a large number of samples. In the current in vitro antibody protection assays, which measure the capacity of antibodies to facilitate phagocytic uptake of C. trachomatis, the phagocytosed bacteria have to be counted manually. This is both labor demanding, time consuming, and it prevents high-throughput usage of this method. In the present study we have therefore developed a simple, rapid flow cytometry based assay to measure the capacity of antibodies to mediate Fc-receptor dependent phagocytosis. This method is highly reproducible and suitable to analyze large numbers of clinical and non-clinical samples.